Dealer Pricing
Pricing from the dealer here was $56 and change so you got lucky.
I have heard that dealers buy their filters from corporate who buys them from a distributor who buys them the manufacture so you have more mark up instead of the Geno's, Cummins, truck stops and other non-dealer stores that only pay the distribution folks.
Highest price paid so far is $18 now I pay $14 delivered to my door.